Vehicle notification sound emitting apparatus

ABSTRACT

A vehicle notification sound emitting apparatus is basically provided with a sound emitting device and a notification sound control device. The sound emitting device is configured to emit a movement notification sound to outside of a vehicle to inform a person in an area surrounding the vehicle that the vehicle will move. The notification sound control device is configured to operate the sound emitting device to emit a movement notification during a period from when a vehicle speed becomes equal to or smaller than a prescribed value until a prescribed amount of time has elapsed in a situation where the vehicle speed becomes equal to or smaller than the prescribed value while the forward movement notification sound is being emitted.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119 to Japanese PatentApplication No. 2010-026114, filed Feb. 9, 2010. The entire disclosureof Japanese Patent Application No. 2010-026114 is hereby incorporatedherein by reference.

BACKGROUND

1. Field of the Invention

The present invention generally relates to vehicle sound emittingtechnology for informing a person in an area surrounding of the vehiclethat the vehicle is moving, or is about to move, in an advancementdirection, e.g., forward or rearward. More specifically, the presentinvention relates to a vehicle notification sound emitting apparatusthat emits a notification sound to inform people of the existence of thevehicle.

2. Background Information

Some vehicles have a very quiet operating sound and/or moving sound(including a vehicle equipped with an internal combustion engine). Forexample, an electric powered vehicle such as an electric car configuredto be electrically driven (EV drive) using only an electric motor istypically very quiet while operating and/or moving. Also for example, ahybrid vehicle having an electric drive mode (EV mode) in which thevehicle is driven solely with an electric motor is typically very quietwhile operating and/or moving. For example, conventional movementnotification sound technology is disclosed in Japanese Laid-Open PatentPublication No. 2005-343360 in which a notification sound emittingapparatus emits a forward movement notification sound for informing aperson in a surrounding area of a vehicle regarding an existence and amoving state of the vehicle during a period from when the vehicle startsmoving until a vehicle speed of the vehicle exceeds a prescribed value.

SUMMARY

It has been discovered that with the conventional technology mentionedabove, since a stopped state of the vehicle is used as a condition forstopping the forward movement notification sound, the notification soundturns on and off frequently when the vehicle is traveling on a congestedroad that results in the vehicle starting and stopping repeatedly forshort intervals. This turning on and off of the notification sound canbecome an annoyance to a person outside the vehicle.

One aspect of the present disclosure is to provide a vehiclenotification sound emitting apparatus that can prevent the notificationsound from turning on and off frequently when the vehicle is travelingon a congested road.

A vehicle notification sound emitting apparatus according to the presentdisclosure is proposed that basically comprises a sound emitting deviceand a notification sound control device. The sound emitting device isconfigured to emit a movement notification sound to outside of a vehicleto inform a person in an area surrounding the vehicle that the vehiclewill move. The notification sound control device is configured tooperate the sound emitting device to emit a movement notification duringa period from when a vehicle speed becomes equal to or smaller than aprescribed value until a prescribed amount of time has elapsed in asituation where the vehicle speed becomes equal to or smaller than theprescribed value while the forward movement notification sound is beingemitted.

These and other objects, features, aspects and advantages of the presentnotification sound emitting apparatus will become apparent to thoseskilled in the art from the following detailed description, which, takenin conjunction with the annexed drawings, discloses a preferredembodiment of the notification sound emitting apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings which form a part of thisoriginal disclosure:

FIG. 1 is a control block diagram showing a control system or vehiclenotification sound emitting apparatus including a notification soundcontroller for controlling a notification sound emitting device of thevehicle notification sound emitting apparatus in accordance with anillustrated embodiment;

FIG. 2 is a flowchart showing a control program executed by thenotification sound controller shown in FIG. 1 in order to controlstarting a starting forward movement notification sound (S sound);

FIG. 3 is a flowchart showing a control program executed by thenotification sound controller shown in FIG. 1 in order to control aforward moving notification sound (D sound);

FIG. 4 is a flowchart showing a control program executed by thenotification sound controller shown in FIG. 1 in order to control areverse movement notification sound (R sound);

FIG. 5 is a flowchart showing a control program executed by thenotification sound controller shown in FIG. 1 in order to prohibitemitting a notification sound from the notification sound emittingdevice; and

FIG. 6 is a flowchart showing a control program executed by thenotification sound controller shown in FIG. 1 in order to increase avolume of a notification sound emitted from the notification soundemitting device.

DETAILED DESCRIPTION OF EMBODIMENTS

Selected embodiments will now be explained with reference to thedrawings. It will be apparent to those skilled in the art from thisdisclosure that the following descriptions of the embodiments areprovided for illustration only and not for the purpose of limiting theinvention as defined by the appended claims and their equivalents.

Referring initially to FIG. 1, a vehicle notification sound emittingapparatus is illustrated in accordance with one embodiment. Morespecifically, FIG. 1 is a control system diagram showing a controlsystem for controlling notification sound emitting devices of thevehicle notification sound emitting apparatus. In this illustratedembodiment, a cabin exterior speaker 1 is provided as an exteriornotification sound emitting device for issuing a notification to aperson (e.g., pedestrian or motorcycle rider) in an outside areasurrounding the vehicle. Also in this illustrated embodiment, a cabininterior speaker 11 is provided as an interior notification soundemitting device for issuing a notification to a driver.

In the illustrated embodiment, a vehicle in which the notification soundemitting apparatus is used is an electric car that has only an electricmotor as a power source and is driven electrically (EV drive) using theelectric motor. However, it should be clear from this disclosure thatthe vehicle notification sound emitting apparatus disclosed herein canalso be applied to a hybrid vehicle having both an electric motor and anengine as power sources, where the vehicle is driven solely with theelectric motor in an electric drive mode (EV mode), and driven withpower from both the electric motor and the engine in a hybrid mode (HEVmode). Likewise, the vehicle notification sound emitting apparatusdisclosed herein can be applied to an engine driven vehicle having onlyan engine as a power source.

In the illustrated embodiment, the cabin exterior speaker 1 is arrangedin a space inside a motor room of a frontward portion of the vehicle.The motor room of the vehicle is where a power unit is located thatincludes an electric motor serving as a power source of the electric carand a transmission. More specifically, the cabin exterior speaker 1 isarranged in a space where mud, rocks, and other contaminants picked upby the wheels will not enter the speaker and such contaminants as rain,snow, and water from a high-pressure car wash will not enter thespeaker. By using this space as a resonance box for the cabin exteriorspeaker 1, the notification sound emitting apparatus according to thisembodiment can be made into a non-directional sound source.

The cabin exterior speaker 1 and the cabin interior speaker 11 arecontrolled by a notification sound controller as shown in FIG. 1. Thenotification sound controller 12 receives signals from a range sensor13, a vehicle speed sensor 14, a brake switch 15, a mute switch 16, asound volume increasing switch 17, an ignition switch 18 and an obstacledistance sensor 19. In this illustrated embodiment, the notificationsound controller 12 corresponds to a notification sound control deviceor section. Basically, the notification sound controller 12 isconfigured to operate the speakers 1 and 11 (e.g., the sound emittingdevices) in response to occurrence of a vehicle condition such asvehicle movement or preparation to vehicle movement. The speakers 1 and11 emit various movement notification sounds depending on the vehiclecondition. The term “movement notification sound” is generically usedherein to refer to both actual vehicle movement as well as preparationfor starting vehicle movement in a forward advancement direction and/ora reverse advancement direction. The term “drivable state” as used herein refers to a vehicle in a nonmoving state but with the vehicle readyto move upon operating an accelerator or the like.

The range sensor 13 is configured to detect if the vehicle transmissionis set to Park (P), Reverse (R), Neutral (N), or Drive (D) by reactingto a shift (range selection) operation performed by a driver to park thevehicle or designate a desired movement direction.

The vehicle speed sensor 14 is configured to detect a vehicle speed V.The brake switch 15 is configured to turn ON when the vehicle is beingbraked by depressing a brake pedal and OFF when the vehicle is not beingbraked (brake pedal is released). The mute switch 16 is configured to bemanually pressed in order to mute a sound emitted from the cabinexterior speaker 1. The sound volume increasing switch 17 is configuredto be pressed in order to increase the volume of a sound emitted fromthe cabin exterior speaker 1. The ignition switch 18 is configured toput the power unit into a drivable state and outputs an ON/OFF signal tothe notification sound controller 12 depending on the position of theignition switch 18. The obstacle distance sensor 19 is configured todetect a distance L between the host vehicle and another vehicle orother obstacle in front of the vehicle.

Now, the manner in which the notification sound controller 12 operatesthe cabin interior speaker 11 in this embodiment will now be explained.In the case where the transmission is shifted to reverse (R), an R rangeselection signal will be received by the notification sound controller12 from the range sensor 13. In response to receiving the R rangeselection signal, the notification sound controller 12 drives the cabininterior speaker 11 to emit an “R range selection notification sound.”The R range selection notification sound informs the driver that the Rrange has been selected. In the illustrated embodiment, the R rangeselection notification sound is an intermittent sound. In the case wherean obstacle's distance L from the host vehicle is smaller than a presetdistance, an obstacle detection signal will be received by thenotification sound controller 12 from the obstacle distance sensor 19.In response to receiving the obstacle detection signal, the notificationsound controller 12 drives the cabin interior speaker 11 to emit an“obstacle proximity notification sound” using, for example, a voice toinform the driver that the vehicle is close to an obstacle.

There are other notification sounds emitted inside the vehicle cabin towarn a driver, such as a “seatbelt notification sound” (not shown in thefigures) emitted to warn that a seatbelt is not latched. However, theseatbelt notification sound is not emitted from the cabin interiorspeaker 11, but from a separate dedicated speaker or buzzer that isdifferent from the cabin interior speaker 11 that is used by thenotification sound controller 12 for notification that the vehicle isclose to an obstacle. In other words, in the illustrated embodiment, thecabin interior speaker 11 is a separate and distinct notification soundemitting device from those used for other notification sounds emittedinside the vehicle cabin.

Operational control of the cabin exterior speaker 1 executed by thenotification sound controller 12 shown in FIG. 1 will now be explained.In this embodiment, the movement notification sounds emitted from thecabin exterior speaker 1 include, but not limited to, a starting forwardmovement notification sound S, a forward moving notification sound D anda reverse movement notification sound R. The starting forward movementnotification sound S (also called “S” sound) is emitted as anotification before the vehicle starts moving forward. The forwardmoving notification sound D (also called “D” sound) serves as a movementnotification sound that is emitted when the vehicle is actually movingforward. The reverse movement notification sound R (also called “R”sound) serving as a movement notification sound emitted when the vehicleis actually moving in reverse and/or has been shifted in a reverse gear.The starting forward movement notification sound (S sound) and theforward moving notification sound (D sound) together constitute aforward advancement notification sound serving to notify about forwardmovement of the vehicle when the vehicle is in the D range.

The starting forward movement notification sound S is a soft soundsimilar to an electronic ring tone produced by a software phone, theforward moving notification sound D is a pseudo engine sound resemblingan engine sound generated when an engine-driven vehicle moves, and thereverse movement notification sound R is the same intermittent sound asthe R range selection notification sound emitted from the cabin interiorspeaker 11 when the R range is selected.

As just mentioned, the forward moving notification sound D is a pseudoengine sound and it is emitted for a long period of time. Consequently,it could be annoying to listen to the forward moving notification soundD continuously, and it is not necessary for a driver to hear the forwardmoving notification sound D.

Conversely, the starting forward movement notification sound S is a softsound like that of a software phone and it is only emitted for a shortperiod of time from immediately before the vehicle starts moving forwarduntil the vehicle starts moving forward. Thus, the starting forwardmovement notification sound S is not annoying to a driver and ispreferably heard by the driver so that the driver can know that astarting forward notification has been emitted.

In view of these requirements, in this embodiment, the forward movingnotification sound D is configured to be a pseudo engine sound as willnow be explained and the starting forward movement notification sound Sis set to a soft sound like that emitted by a software phone as will beexplained later.

In view of the propagation properties of sound between the inside andoutside of the vehicle cabin, a vehicle is typically constructed suchthat sounds with comparatively high frequencies (typically 1.5 kHz to 6kHz, although it varies depending on the vehicle) do not easilypenetrate the cabin interior from outside the cabin. However, a vehicleis typically constructed such that sounds with comparatively lowfrequencies (typically below 1.5 kHz, although it varies depending onthe vehicle) do easily penetrate the cabin interior from outside thecabin. Therefore, in this embodiment, the forward moving notificationsound D is configured to be a pseudo engine sound in a prescribed rangeof comparatively high frequencies (preferably 2 kHz to 4 kHz) that donot easily enter the cabin interior from outside the cabin. In this way,the forward moving notification sound D is not heard unnecessarily by adriver inside the vehicle cabin. As a result, the forward movingnotification sound D (pseudo engine sound) does not become an annoyanceto the driver. Moreover, forward moving notification sound D (pseudoengine sound) is readily heard by a person in an outside areasurrounding the vehicle and reliably informs the person of the existenceand movement of the vehicle.

However, if the starting forward movement notification sound S is set toa sound (e.g., pseudo engine) similar to the forward moving notificationsound D, then the starting forward movement notification sound S willneed to be set to a volume larger than the volume of the car horn inorder for a driver inside the vehicle cabin to be able to hear thestarting forward movement notification sound S and recognize that theforward movement start notification has been issued. However, at such avolume, a person in the surrounding area will be startled by the sound.

Therefore, in this embodiment, the forward movement start sound (Ssound) is set to be a soft sound like an electronic ring tone of asoftware phone that lies in a comparatively low frequency range thatreadily penetrates the inside of the vehicle cabin from outside thevehicle. Due to its low frequency, such a starting forward movementnotification sound S readily penetrates the inside of the vehicle cabinfrom outside the vehicle such that a driver inside the vehicle cabin canhear the starting forward movement notification sound S and unmistakablyrecognize that the forward movement start notification has been issuedwithout the forward movement notification sound being set to a largevolume (i.e., without startling people in a surrounding area). Also, thestarting forward movement notification sound S is not annoying orunpleasant to a driver because it is a soft sound like that of asoftware phone and it is only emitted for a short period fromimmediately before the vehicle starts moving forward until the vehiclestarts moving forward.

In order to control the starting forward movement notification sound S,the notification sound controller 12 of FIG. 1 executes the controlprogram shown in FIG. 2. In step S11, the notification sound controller12 checks if the vehicle is in a drivable state. This determination canbe accomplished by comparing a current vehicle speed V with a stopdetermination vehicle speed Vs (e.g., Vs=1 km/h) and/or checking thestate of the ignition switch being ON or OFF. If a current vehicle speedV is smaller than the stop determination vehicle speed Vs and theignition switch is ON, then the notification sound controller 12determines a drivable state exists. If the vehicle speed V is equal toor larger than the stop determination vehicle speed Vs (e.g., Vs=1 km/h)such that the vehicle is determined to be in a moving state or if theignition switch is OFF such that the vehicle is in a non-drivable state,then the notification sound controller 12 ends the control sequence andskips step S15 such that the starting forward movement notificationsound S is not emitted. Thus, in step S11, the notification soundcontroller 12 determines that the vehicle is stopped but in a drivablestate by checking that the vehicle speed is below a prescribed value andthat the state of the ignition switch 18 is ON. In this illustratedembodiment, step S11 of the process executed by the notification soundcontroller 12 corresponds to a movement state detecting device orsection.

If the notification sound controller 12 determines that the vehicle isstopped (i.e., V<Vs) and that the vehicle is in a drivable state(ignition switch 18 is ON) in step S11, then the notification soundcontroller 12 proceeds to step S12. In step S12, the notification soundcontroller 12 determines if an operation changing the range to the Drange (shifted to the drive (D) position) occurred while the brakeswitch 15 was in an OFF state (i.e., the brake not being operated). Ifthe result of step S12 is Yes, then the notification sound controller 12proceeds to step S15. In step S15, the notification sound controller 12drives the cabin exterior speaker 1 such that a soft sound resembling anelectronic ring tone of a software phone.

If the result of step S12 is No, then the notification sound controller12 proceeds to step S13. In step S13, the notification sound controller12 determines if the brake switch 15 changed from ON to OFF (i.e., ifthe brake pedal changed from a depressed braking state to a releasednon-braking state) while the D range was in a selected state. If theresult of step S13 is Yes, then the notification sound controller 12proceeds to step S15. In step S15, the notification sound controller 12drives the cabin exterior speaker 1 such that a soft S sound resemblingan electronic ring tone of a software phone is emitted. In thisillustrated embodiment, step S13 of the process executed by thenotification sound controller 12 corresponds to a start movementintention detecting section or device.

If the result of step S13 is No, then the notification sound controller12 proceeds to step S14 and determines if a change to the D rangeoccurred simultaneously or substantially simultaneously with the brakeswitch 15 being changed from ON to OFF (i.e., if the brake pedal changedfrom a depressed braking state to a released non-braking state). If theresult of step S14 is Yes, then the notification sound controller 12proceeds to step S15 and drives the cabin exterior speaker 1 such that asoft S sound resembling an electronic ring tone of a software phone isemitted.

In steps S13 and S14, if the brake pedal is being returned slowly from adepressed state and the driver's foot has not yet separated from thebrake pedal, then the brake switch 15 will still be ON and not yetchanged to OFF. Consequently, the notification sound controller 12 willnot proceed to step S15 and the starting forward movement notificationsound S cannot be emitted.

If the driver were to mistakenly think that the starting forwardmovement notification sound S had been emitted while the driver wasslowly (gradually) returning the brake pedal, then the driver mightstart driving while believing that any person in a surrounding area ofthe vehicle had been warned by the starting forward movementnotification sound S that the vehicle would be starting into motion.This would be undesirable from a safety perspective. Furthermore, whilethe brake pedal is undergoing a slow brake pedal return operation, thereis a possibility that the braking force will decline and the vehiclewill start moving due to, for example, a creep force or a downward slopeof a road surface. Thus, caution is necessary to ensure safety.

However, in this embodiment, as mentioned previously, the startingforward movement notification sound S is a notification sound in acomparatively low frequency range that easily penetrates the inside ofthe vehicle cabin from outside the vehicle and can be readily heard bythe driver. Thus, since the driver can easily recognize when the forwardmovement start notification has been issued, the driver can also easilyrecognize that the starting forward movement notification sound S wasnot emitted during a slow brake pedal return operation. As a result,with this embodiment, the driver will not mistakenly believe that thestarting forward movement notification sound S was emitted during a slowbrake pedal return operation. In other words, the driver will assumethat a person near the vehicle has not heard the starting forwardmovement notification sound S and is not aware that the vehicle willstart moving if the driver has not heard the starting forward movementnotification sound S. Thus, the driver can strive to drive safely and agreat advantage in terms of driving safety can be achieved.

If the result of step S14 is No, then the notification sound controller12 ends the control loop and skips step S15 such that the startingforward movement notification sound S is not emitted.

In short, the notification sound controller 12 drives the cabin exteriorspeaker 1 such that the starting forward movement notification sound Sis emitted when any of the following conditions occurs while the vehicleis stopped (V<Vs) and in a drivable state (ignition switch 18 is ON)(step S11): (1) an operation changing the range to the D range occurswhile the brake pedal is in a released non-braking state (step S12); (2)the brake pedal changes from a depressed braking state to a releasednon-braking state while the D range is in a selected state (step S13);or (3) an operation changing the range to the D range occurssimultaneously with the brake pedal changing from a depressed brakingstate to a released non-braking state (step S14). Otherwise, the cabinexterior speaker 1 remains in a non-driven state and the startingforward movement notification sound S is not emitted.

In this embodiment, the starting forward movement notification sound Sis emitted immediately before the vehicle starts moving when the vehicleis stopped in a drivable state (step S11) and a shift operation changingthe range to the D range occurs while the brake pedal is in a released(non-braking) state (step S12), a foot depressing the brake pedalreleases the brake pedal while the D range is in a selected state (stepS13), or a shift operation changing the range to the D range occurssimultaneously with a brake release operation in which a foot depressingthe brake pedal is released from the brake pedal (step S14). In otherwords, in these situations, the starting forward movement notificationsound S is emitted immediately by the cabin exterior speaker 1 beforethe vehicle starts moving (step S15).

If the apparatus were configured to emit the starting forward movementnotification sound S when the vehicle enters a drivable state due to theignition switch 18 being turned ON, then the starting forward movementnotification sound S would be emitted too soon and the starting forwardmovement notification sound S would be emitted unnecessarily during aperiod from when the vehicle entered the drivable state untilimmediately before the vehicle starts moving. Consequently, the startingforward movement notification sound S would be emitted for a long timeuntil the vehicle started moving and would bother people (e.g.,pedestrians) in an area surrounding the vehicle. Conversely, if thestarting forward movement notification sound S is emitted after thevehicle starts moving, then the starting forward movement notificationsound S will not serve its purpose of notification that the vehicle willstart moving and the meaning of the notification sound will bediminished.

With this embodiment, however, since the starting forward movementnotification sound S is emitted immediately before the vehicle startsmoving, such a problem as the starting forward movement notificationsound S being emitted for a long time before the vehicle starts movingand confusing people (e.g., pedestrians) in a surrounding area or themeaning of the notification provided by the starting forward movementnotification sound S being diminished can be avoided.

In order to control the forward moving notification sound D, thenotification sound controller 12 of FIG. 1 executes the control programshown in FIG. 3. In step S21, the notification sound controller 12checks if the starting forward movement notification sound S is beingemitted by actuation of the cabin exterior speaker 1. If the startingforward movement notification sound S is being emitted, then thecontroller 12 proceeds to step S22. In step S22, the notification soundcontroller 12 checks if a prescribed amount of time has elapsed sincethe starting forward movement notification sound S started to be emitted(e.g., 500 msec). The controller 12 ends the control loop and continuesemitting the starting forward movement notification sound S until theprescribed amount of time (500 msec) elapses.

When the notification sound controller 12 determines in step S22 thatthe prescribed amount of time (500 msec) has elapsed since emission ofthe starting forward movement notification sound S started, i.e., afterthe starting forward movement notification sound S has been emittedcontinuously for the prescribed amount of time, the controller 12proceeds to step S23. In step S23, the notification sound controller 12executes a cross fade from the starting forward movement notificationsound S to the forward moving notification sound D. The cross fade fromthe starting forward movement notification sound S to the forward movingnotification sound D involves gradually lowering a sound pressure levelof the starting forward movement notification sound S while graduallyincreasing a sound pressure level of the forward moving notificationsound D (pseudo engine sound) such that the operating state of the cabinexterior speaker 1 gradually changes from the starting forward movementnotification sound S to the forward moving notification sound D. As aresult, the change from the starting forward movement notification soundS to the forward moving notification sound D can be accomplished withoutcausing a person (e.g., a pedestrian) in a surrounding area toexperience an odd feeling about the sounds from the vehicle.

In this embodiment, since the starting forward movement notificationsound S is emitted immediately before the vehicle starts moving asdescribed previously with reference to FIG. 2 (steps S12 to S15 in FIG.2), the starting forward movement notification sound S is emitted at anappropriate timing for notification that the vehicle will start moving.As explained above, the forward moving notification sound D is alsoemitted at an appropriate timing following the starting forward movementnotification sound S. As a result, a situation in which the forwardmoving notification sound D is emitted long before the vehicle startsmoving can be avoided. In this way, the movement notification sound willnot cause people (e.g., pedestrians) in a surrounding area to beperplexed and the meaning of the forward movement notification providedby the forward moving notification sound D to be diminished.

If the controller 12 determines in step S21 that the starting forwardmovement notification sound S is not being emitted from the cabinexterior speaker 1, the controller 12 proceeds to step S24 where thecontroller 12 checks if the ignition switch 18 is ON, i.e., if thevehicle is in a drivable state. If the controller 12 determines that thevehicle is in a drivable state, then the controller 12 proceeds to stepS25. In step S25, the controller 12 checks if the Drive or D range is ina selected state (i.e., if the D range has been selected). If the Drange has been selected, then the controller 12 proceeds to step S26. Instep S26, the controller 12 determines if the vehicle speed V is equalto or larger than the stop determination vehicle speed Vs, i.e., if thevehicle is moving. If the controller 12 determines that the vehicle isin a drivable state in step S24, that the D range is selected in stepS25, and that the vehicle is moving (V≧Vs) in step S26, then thecontroller 12 proceeds to step S27. In step S27, the controller 12drives the cabin exterior speaker 1 such that the forward movingnotification sound D (pseudo engine sound) is emitted.

The forward moving notification sound D is a pseudo engine sound, asexplained previously. The sound volume level of the forward movingnotification sound D is held constant. Meanwhile, a frequency of theforward moving notification sound D is set to increase as the vehiclespeed increases while remaining within a comparatively high frequencyrange in which the forward moving notification sound D cannot easilypenetrate the cabin interior from outside the cabin. The frequency ofthe forward moving notification sound D is set based on a detectedvehicle speed. Thus, in this first embodiment, the speed sensor 14corresponds to a frequency setting device or section. In the firstembodiment, the frequency is set to have a linear relationship withrespect to the vehicle speed, but it is also acceptable to set thefrequency to be an upwardly convex or concave curve in the manner of anexponential function. The sound volume level is not changed but set to aprescribed constant value (corresponds to a sound volume setting sectionor device); only the frequency is changed. When the forward movingnotification sound D is produced in this way as a pseudo engine soundwhose sound pressure level stays constant and whose frequency increasesas the vehicle speed increases, a person outside the vehicle can judge adistance to the vehicle based on the volume of the forward movingnotification sound D. In particular, as the volume of the forward movingnotification sound D becomes larger, the person can determine thevehicle is getting closer. Since the volume of the sound emitted fromthe vehicle is constant, the sound pressure perceived by a personoutside the vehicle differs according to distance. Therefore, a personoutside the vehicle can judge the distance between him or her and thevehicle based on a difference in sound pressure. Also, the person canjudge a speed of the vehicle based on the pitch of the forward movingnotification sound D. The higher the pitch of the forward movingnotification sound D is, the higher the vehicle speed is. Thus, basedsolely on the forward moving notification sound D, the person can knowapproximately how close the vehicle is and how fast it is approaching.

In step S28, the controller 12 determines if the vehicle speed V hasreached or exceeded a prescribed vehicle speed (30 km/h), since movementstarted. This prescribed vehicle speed (30 km/h) corresponds to aminimum prescribed vehicle speed value at which the forward movingnotification sound D is no longer necessary. This prescribed vehiclespeed (30 km/h) is also called the D sound fade-out speed. Thus, uponthe vehicle reaching the D sound fade out speed, the controller 12starts fading out the forward moving notification sound D. If the resultof step S28 is No, then the controller 12 proceeds to step S29 anddetermines if the vehicle speed V is below a prescribed D sound fade-inspeed. In this embodiment, the prescribed D sound fade-in speed is setto 25 km/h, which is lower than the D sound fade-out speed of 30 km/h(minimum vehicle speed value at which the forward moving notificationsound D is not necessary) by a hysteresis amount (5 km/h). If thecontroller 12 determines in step S28 that since vehicle started movingthe vehicle speed V has become equal to or larger than the D soundfade-out speed of 30 km/h, then the controller 12 proceeds to step S31.In step S31, the controller 12 drives the cabin exterior speaker 1 suchthat the forward moving notification sound D emitted in step S27gradually decreases and disappears (fades out).

If the controller 12 determines in step S29 that the vehicle speed V isbelow the D sound fade-in speed of 25 km/h, then the controller 12proceeds to step S32. In step S32, the controller 12 checks if theforward moving notification sound D is being emitted. If the forwardmoving notification sound D has been stopped due to executing step S31,then the controller 12 proceeds to step S33 where the controller 12drives the cabin exterior speaker 1 such that the forward movingnotification sound D gradually increases from a sound pressure level of0 (such that the forward moving notification sound D fades in). If thecontroller 12 determines in step S32 that the forward movingnotification sound D is being emitted, then the controller 12 ends thecontrol loop and continues operating the cabin exterior speaker suchthat the forward moving notification sound D is emitted.

If the controller 12 determines in step S29 that the vehicle speed V isequal to or higher than the D sound fade-in speed (25 km/h), i.e., ifcontroller 12 determines that the vehicle speed V is in a hysteresisregion between the D sound fade-out speed 30 km/h and the D soundfade-in speed 25 km/h, then the controller 12 ends the control loop suchthat the current operating state of the cabin exterior speaker 1 ismaintained and the forward moving notification sound D continues to beemitted in the current manner.

If the controller 12 determines in step S24 that the ignition switch 18is OFF, i.e., that the vehicle is in a non-drivable state, then theforward moving notification sound D is not necessary and the controller12 proceeds to step S31. In step S31, the controller 12 drives the cabinexterior speaker 1 such that the forward moving notification sound Dfades out.

If the controller 12 determines in step S25 that the D range is notselected or if the controller 12 determines that the D range is still ina selected state but determines that the vehicle is stopped in step S26,then the forward moving notification sound D is not necessary and thecontroller 12 needs to drive the cabin exterior speaker 1 such that theforward moving notification sound D fades out. However, in this case,the forward moving notification sound D control is handled in a specialmanner that will now be explained.

In step S34, the controller 12 determines if the vehicle speed V hasbeen continuously at a vehicle speed equal to or smaller than aprescribed value (V≦Vs km/h), which is at or near zero, for a prescribedamount of time (10 seconds in this embodiment). If the determinationresult is Yes in step S34, then the controller 12 proceeds to step S31and drives the cabin exterior speaker 1 such that the forward movingnotification sound D fades out. The prescribed amount of time set instep S34 is preferably the amount of time for determining if the vehicleis waiting at a traffic light or traveling on a congested road. It isacceptable to vary the prescribed amount of time by measuring a stoptime occurring on a congested road and setting the prescribed amount oftime automatically or by allowing a driver to set the prescribed amountof time manually in consideration of a stop time occurring on acongested road. Alternatively, the prescribed amount of time can bevariably set based on information provided by a vehicle navigationsystem or other information provided to the vehicle about the area inwhich the vehicle is traveling.

If the controller 12 determines in step S34 that the vehicle speed V isabove the prescribed value (Vs), i.e., that the vehicle is not stopped,or that the vehicle is in a stopped or near stopped state but thestopped state or near stopped state has not continued for at least theset amount of time (10 seconds), then the controller 12 proceeds to stepS35. In step S35, the controller 12 determines if the vehicle is set topark (P), neutral (N), or another non-driving range. In this illustratedembodiment, step S35 corresponds to a driving continuance intentdetermining section or device. If the determination result is Yes instep S35, then the controller 12 proceeds to step S36. In step S36, thecontroller 12 determines if the vehicle speed V is smaller than the stopdetermination vehicle speed Vs, i.e., if the vehicle can be deemedsubstantially stopped. If the determination result is Yes in step S36,then the controller 12 proceeds to step S31. In step S31, the controller12 drives the cabin exterior speaker 1 such that the forward movingnotification sound D fades out.

In other words, even if the controller 12 has determined in step S34that the vehicle is not in a stopped state or near stopped state withthe vehicle speed V above the prescribed value (Vs) or that the vehicleis in a stopped state or near stopped state but has not been in thestopped state or near stopped state continuously for at least a setamount of time (10 seconds), then the controller 12 still executes afade out of the forward moving notification sound D (step S31) if theselected range is a non-driving range (park or neutral) (step S35) andthe vehicle speed V is below the stop determination vehicle speed Vs(step S36).

However, if the selected range is determined not to be a non-drivingrange (park or neutral) in step S35, or if the selected range isdetermined to be a non-driving range (park or neutral) in step S35 butthe vehicle speed V is determined to be equal to or larger than the stopdetermination vehicle speed Vs (i.e., the vehicle is determined to bemoving) in step S36, then it is necessary to emit the forward movingnotification sound D. Thus, the controller 12 proceeds to step S27 wherethe controller 12 continues to drive the cabin exterior speaker 1 suchthat the forward moving notification sound D is emitted.

When the range is changed from the D range to a non-driving range (parkor neutral), there is a possibility that the vehicle will still move dueto inertia. Thus, the apparatus is configured to continue emitting theforward moving notification sound D from the cabin exterior speaker 1when the selected range is determined to be a non-driving range (park orneutral) in step S35 but the vehicle speed V is determined to be equalto or larger than the stop determination vehicle speed Vs (i.e., thevehicle is determined to be moving) in step S36. In this way, a personwho is in a vicinity of a front end portion of the vehicle when thevehicle moves due to inertia in such a case can be urged to exercisecaution by the movement notification sound.

In this embodiment, when the controller 12 determines that the D rangeis not in a selected state in step S25 or when the D range is still in aselected state but the controller 12 determines that the vehicle isstopped in step S26, the controller does not proceed immediately to stepS31 and fade the forward moving notification sound D out. Instead, thecontroller 12 continues emitting the forward moving notification sound Duntil it executes step S34 and only then proceeds to step S31. In stepS31, the controller 12 fades the forward moving notification sound D outif the controller 12 determines that the vehicle speed V has equaled 0km/h, i.e., that the vehicle has been in a stopped state, for a setamount of time (10 seconds). Thus, when the vehicle is on a congestedroad or in another situation in which the vehicle stops but the vehiclespeed V does not remain at 0 km/h (stopped state) for the set amount oftime (10 seconds), an annoying situation can be avoided in which theforward moving notification sound D fades out and then again emitted inaccordance with the starting forward movement notification sound Scontrol shown in FIG. 2 (step S15) every time the vehicle stops. Inorder to achieve this objective even more effectively, it is acceptableto vary the prescribed amount of time by measuring a stop time occurringon a congested road and setting the prescribed amount of timeautomatically or by allowing a driver to set the set amount of timemanually in consideration of a stop time occurring on a congested road.

In this embodiment, the starting forward movement notification sound Sis emitted in step S15 of FIG. 2 when the controller 12 is determined instep S13 or step S14 that the brake pedal has been released and thebrake switch 15 has changed from ON to OFF. Consequently, when the brakepedal is being released gradually from a depressed state but the brakepedal has not yet been released, the starting forward movementnotification sound S is not emitted, i.e., the step S15 is not executed,until the brake switch 15 changes from ON to OFF.

During a slow brake pedal return operation, there is a possibility thatthe braking force will decline and the vehicle will start moving due to,for example, a creep force or a downward slope of a road surface.Therefore, it is necessary to warn a person in a vicinity of the vehicleif the vehicle starts to move. However, since a notification of avehicle starting to move in this manner would occur after the vehiclehas started to move, the forward moving notification sound D is moreappropriate than the starting forward movement notification sound S

In this embodiment, as shown in FIG. 3, the controller 12 proceeds fromstep S21 of FIG. 3 to steps S24 to S26 during a situation in which thebrake pedal is undergoing a slow return operation such that the startingforward movement notification sound S is not emitted. If the controller12 determines in step S26 that the vehicle speed V is equal to or largerthan the stop determination vehicle speed Vs, i.e., that the vehicle ismoving, then the controller proceeds to step S27 and emits the forwardmoving notification sound D. Consequently, the forward movingnotification sound D is emitted instead of the starting forward movementnotification sound S when the vehicle starts moving while the brakepedal is undergoing a slow return operation. As a result, when thevehicle starts moving during a slow brake return operation as explainedabove, a person in a surrounding area can be warned reliably with themore appropriate forward moving notification sound D instead of thestarting forward movement notification sound S.

In order to control the reverse movement notification sound R (R sound),the notification sound controller 12 executes the control program shownin FIG. 4. In step S41, the controller 12 checks if the ignition switch18 is ON, i.e., if the vehicle is in a drivable state. If the vehicle isin a drivable state, then the controller 12 proceeds to step S42. Instep S42, the controller 12 checks if vehicle has been placed in reverse(i.e., if the range is set to the R range). If the vehicle is in reverse(R range), then the controller 12 proceeds to step S43. In step S43, thecontroller 12 drives the cabin exterior speaker 1 such that the reversemovement notification sound R is emitted. Thus, the reverse movementnotification sound R is emitted before the vehicle actually startsmoving.

Thus, when the ignition switch 18 is ON, i.e., the vehicle is in adrivable state, (step S41) and the vehicle is in reverse, i.e., the Rrange (step S42), the reverse movement notification sound R is emittedfrom the cabin exterior speaker 1 immediately (step S43). Since thereverse movement notification sound R is emitted from the cabin exteriorspeaker 1 immediately when the vehicle is in reverse, i.e., the R range(steps S42 and S43), an “R range selection notification sound” isemitted from the cabin interior speaker 11 simultaneously while thevehicle is in reverse (R range), as explained previously. 100651 Asexplained previously, since the reverse movement notification sound Remitted from the cabin exterior speaker 1 in step S43 serves to conveythe same type of vehicle information as the R range selectionnotification sound emitted from the cabin interior speaker 11, thereverse movement notification sound R emitted from the cabin exteriorspeaker 1, too, is configured to be an intermittent sound. The reversemovement notification sound R (intermittent sound) is controlled to besynchronized with the intermittent R range selection notification soundemitted from the cabin interior speaker 11. Thus, in this embodiment,step S43 constitutes cabin interior-exterior notification soundsynchronizing section.

It is also acceptable if, conversely, the intermittent R range selectionnotification sound emitted from the cabin interior speaker 11 issynchronized with the reverse movement notification sound R(intermittent sound) emitted from the cabin exterior speaker 1.

Either way, the reverse movement notification sound R (intermittentsound) emitted from the cabin exterior speaker 1 and the R rangeselection notification sound emitted simultaneously from the cabininterior speaker 11 are synchronized and the R sound from the cabinexterior speaker 1 (which the driver does not need to hear) is overlaidwith the intermittent R range selection notification sound from thecabin interior speaker 11 such that the driver cannot hear it. Thus, theproblem of the driver hearing and being annoyed by the unnecessary Rsound emitted from the cabin exterior speaker 1 can be alleviated.

Additionally, since the reverse movement notification sound R(intermittent sound) is synchronized with the intermittent R rangeselection notification sound, the intermittent periods when neither thereverse movement notification sound R (intermittent sound) from thecabin exterior speaker 1 nor the intermittent R range selectionnotification sound from the cabin interior speaker 11 can be heard,i.e., the periods when the driver can easily hear another notificationsound, are longer. Thus, during these longer quiet periods, such othernotification sounds as the obstacle proximity notification sound and theseatbelt notification sound mentioned previously can be heard by adriver. In this way, the driver can recognize the notification soundsimmediately and obtain the corresponding information reliably, which isgreatly advantageous from a safety standpoint.

If the controller 12 determines in step S41 that the ignition switch 18is OFF, i.e., that the vehicle is in a non-drivable state, then thevehicle cannot move in reverse and it is not necessary to emit the Rsound. Therefore, the controller 12 ends the control loop directly andskips step S43 such that the R sound is not emitted (i.e., the cabinexterior speaker 1 is put into a non-driven state).

If the controller 12 determines in step S42 that the R range is notselected, then the controller 12 proceeds to step S44 and determines ifa non-driving range (park or neutral) is selected. If the controller 12determines that the vehicle is not set to a non-driving range (park orneutral), i.e., that the D range is selected, then it is not necessaryto emit the reverse movement notification sound R and the controller 12ends the control loop directly, thereby skipping step S43 such that thereverse movement notification sound R is not emitted (i.e., the cabinexterior speaker 1 is put into a non-driven state).

If the controller 12 determines in step S44 that the vehicle is set to anon-driving range (park or neutral), then the controller 12 proceeds tostep S45 and checks if the vehicle speed V is smaller than the stopdetermination vehicle speed Vs, i.e., if the vehicle can be deemedsubstantially stopped. If the controller 12 determines that the vehicleis substantially stopped, then the controller 12 proceeds to step S46.In step S46, the controller 12 drives the cabin exterior speaker 1 suchthat the reverse movement notification sound R emitted in step S43gradually decreases until it disappears (fades out).

However, if the controller 12 determines that the vehicle is in anon-driving range (park or neutral) in step S44 but that the vehiclespeed V is not smaller than the stop determination vehicle speed Vs(i.e., the vehicle is not substantially stopped but determined to bemoving), then the controller 12 determines that the vehicle is moving inreverse even though it is in a non-driving range (park or neutral) andproceeds to step S47. In step S47, the controller 12 continues drivingthe cabin exterior speaker 1 such that the reverse movement notificationsound R is started emitting in step S43 continues to be emitted. In thisway, in a situation in which the vehicle continues moving in reverse dueto inertia after the range is changed from the R range to a non-drivingrange (park or neutral), the reverse movement notification sound R cancontinue to be emitted from cabin exterior speaker 1. In this way, aperson near a rear end portion of the vehicle can be reliably warnedthat the vehicle is moving backward and be urged to exercise caution.

A situation in which the reverse movement notification sound R isemitted in step S47 can only occur if the controller 12 has determinedin step S42 that the R range is not in a selected state. In such asituation, as should be clear from the previous explanation, the R rangeselection notification sound is not emitted from the cabin interiorspeaker 11 and, thus, it is not necessary to synchronize an R rangeselection notification sound emitted from the cabin interior speaker 11with the R sound from the cabin exterior speaker 1 as is done in stepS43.

As explained previously with reference to FIGS. 2 and 3, the forwardmoving notification sound D is emitted when a prescribed amount of time,e.g., 500 msec, has elapsed (step S22 of FIG. 3) since the startingforward movement notification sound S started being emitted (step S15 ofFIG. 2) in response to the D range being selected by a driver from astopped state (step S11 of FIG. 2) and an operation being performed bythe driver in preparation to start the vehicle into motion, e.g.,releasing the brake pedal, (steps S12 to S14 of FIG. 2). Conversely, asexplained previously with reference to FIG. 4, the reverse movementnotification sound R is emitted immediately (step S43 of FIG. 4) whenthe driver selects the R range (step S42 of FIG. 4). The reason thereverse movement notification sound R is emitted immediately will now beexplained.

A vehicle is intended chiefly for driving forward and driving in reverseis more difficult for a driver than driving forward. Moreover, a person(e.g., a pedestrian) in a surrounding area of a vehicle tends to assumethat a vehicle typically moves in a forward direction and naturallyexercises caution with respect to forward movement of a vehicle.Conversely, a person does not expect a vehicle to move in reverse andtends to exercise less caution in anticipation of reverse movement.

In short, the reverse movement notification sound R is intended as anotification of reverse movement indicating movement in a direction adriver is less accustomed to and a direction a person (e.g., apedestrian) in a surrounding area is less likely to expect. Therefore,from a safety standpoint, it is preferable for the reverse movementnotification sound R to be emitted as early as possible to urge peoplein a surrounding area to exercise caution. Conversely, the forwardmoving notification sound D is intended as a notification of forwardmovement indicating movement in a direction a driver is more accustomedto and a direction a person (e.g., a pedestrian) in a surrounding areais more likely to expect as a natural direction for a vehicle to move.Moreover, as explained previously, the forward moving notification soundD is a pseudo engine sound and it is better to keep an emission time ofthe forward moving notification sound D as short as possible in order toensure the quietness of the vehicle. Therefore, it is preferable for theforward moving notification sound D to be emitted as late as possible.

Thus, as mentioned above, each notification sound (the S sound, the Dsound and the R sound) is emitted under different respective vehicleconditions in this embodiment. In particular, in this embodiment, theapparatus is configured such that the reverse movement notificationsound R is emitted immediately (step S43 of FIG. 4) when a driverperforms an operation selecting the R range (step S42 of FIG. 4). Also,in this embodiment, the apparatus is configured such that the forwardmoving notification sound D is emitted after a prescribed amount oftime, e.g., 500 msec, has elapsed (step S22 of FIG. 3) since thesoftware phone-like sound of the starting forward movement notificationsound S was started being emitted (step S15 of FIG. 2) in response tothe D range being selected by a driver from a stopped state (step S11 ofFIG. 2) and an operation being performed by the driver in preparation tostart the vehicle into motion, e.g., releasing the brake pedal, (stepsS12 to S14 of FIG. 2). By configuring the apparatus in this way, thenotification sounds emitted for forward movement and reverse movementcan each be emitted at a necessary timing and for a necessary period oftime without confusing a person (e.g., a pedestrian) in a surroundingarea by emitting unnecessary notification sounds. In this embodiment,steps S12 to S15 of FIG. 2 constitute a notification sound emissiontiming section.

There are situations in which a notification sound (e.g., the S sound,the D sound, and the R sound) emitted from the cabin exterior speaker 1like the starting forward movement notification sound S, the forwardmoving notification sound D, or the reverse movement notification soundR could be an annoying disturbance to others, such as late at night orin a residential neighborhood. In such a situation, a driver can issue anotification sound prohibition command by pressing the mute switch 16shown in FIG. 1. The mute switch 16 is configured to issue anotification sound prohibition command each time it is pressed such thatit enters an ON state. When it is not being pressed, it automaticallyresumes a normal position (OFF position).

When the controller 12 receives the notification sound prohibitioncommand from the mute switch 16, the controller 12 shown in FIG. 1executes a control program shown in FIG. 5 and prohibits emission ofnotification sounds (the S sound, the D sound and the R sound) as willnow be explained.

In step S51, the controller 12 checks if the mute switch 16 has beenturned ON, i.e., if the notification sound prohibition command has beenissued. If the mute switch 16 is not ON (if the notification soundprohibition command has not been issued), then the controller 12 endsthe control loop and does not execute a prohibition of the notificationsounds. As a result, the notification sounds are emitted as explainedpreviously with reference to FIGS. 2 to 4.

If the controller 12 determines in step S51 that the mute switch 16 hasbeen turned ON (that the notification sound prohibition command has beenissued), then the controller 12 proceeds to step S52. In step S52, thecontroller 12 prohibits the emission of notification sounds such thatthe notification sounds (the S sound, the D sound and the R sound) arenot emitted from the cabin exterior speaker 1 regardless of the state ofthe controls shown in FIGS. 2 to 4.

Next, in step S53, the controller 12 determines if the vehicle speed Vis equal to or larger than the 30 km/h, which is a minimum vehicle speedvalue at which the forward moving notification sound D is not necessary(D sound fade-out vehicle speed) as explained previously regarding stepS28 of FIG. 3. If the result of this determination is No in step S53,then the controller 12 ends the control loop and continues thenotification sound emission prohibition started in step S52. If thecontroller 12 determines in step S53 that the vehicle speed V is equalto or larger than the D sound fade-out speed (30 km/h), then thecontroller 12 proceeds to step S54. In step S54, the controller 12cancels the notification sound emission prohibition started in step S52,thereby allowing the notification sounds (the S sound, the D sound andthe R sound) to be emitted from the cabin exterior speaker 1 inaccordance with the controls shown in FIGS. 2 to 4.

With the notification sound prohibition control just described, a drivercan prohibit the emission of notification sounds (the S sound, the Dsound and the R sound) from the cabin exterior speaker 1 (step S52)regardless of the state of the controls shown in FIGS. 2 to 4 bypressing the mute switch 16 (step S51). Thus, emission of thenotification sounds can be prevented in situations where a notificationsound emitted from the cabin exterior speaker 1, i.e., the startingforward movement notification sound S, the forward moving notificationsound D, or the reverse movement notification sound R, could be anannoying disturbance to other people (e.g., pedestrians) in asurrounding area, such as late at night or in a residentialneighborhood.

However, if the emission of notification sounds continues to beprohibited after the driver presses the mute switch 16, then thenotification sounds will not be emitted even after the vehicle hastraveled to an area where the notification sounds will not be adisturbance and the apparatus will not serve its purpose as a safetydevice. Therefore, in this embodiment, if the vehicle speed V reaches orexceeds the D sound fade-out speed (30 km/h) (step S53), then thecontroller 12 determines that the vehicle has traveled to a place wherethe notification sounds will not disturb anyone and cancels thenotification sound emission prohibition (step S54). In this way, thenotification sounds (the S sound, the D sound and the R sound) can beemitted from the cabin exterior speaker 1 in accordance with thecontrols shown in FIGS. 2 to 4.

By canceling the prohibition in this way, a situation in which thenotification sounds are not emitted even after the vehicle has traveledto a place where the notification sounds will not disturb anyone beavoided and the notification apparatus can serve its purpose as a safetyapparatus.

In this embodiment, the vehicle speed V reaching or exceeding the Dsound fade-out speed (30 km/h) is used as a condition for canceling thenotification sound prohibition. Certain operational effects can beobtained by contriving the apparatus to determine that the vehicle hastraveled to a place where the notification sounds will not disturbanyone and cancel the notification sound prohibition when that conditionis satisfied. Those effects will now be explained.

If the condition for canceling the notification sound prohibition is setto a vehicle speed V that is slower than the forward moving notificationsound D fade out vehicle speed (30 km/h), then it will be possible forthe prohibition to be canceled while the vehicle is still in a placewhere the notification sounds could disturb other people in asurrounding area. More specifically, as explained previously, the regionof low vehicle speeds below 30 km/h is the region in which the apparatusis configured to emit the forward moving notification sound D.Meanwhile, it is in this same low vehicle speed region that a drivermight press the mute switch 16 (turns it ON) to prohibit thenotification sounds from being a disturbance. If the cancellationcondition is a vehicle speed in this low vehicle speed region, then thenotification sound prohibition might be cancelled immediately after adriver releases his or her finger from the mute switch 16, thus allowinga notification sound to disturb a person (e.g., a pedestrian) in asurrounding area of the vehicle.

In this embodiment, however, the condition for cancelling thenotification sound prohibition is that the vehicle speed V is equal toor larger than the D sound fade-out speed (30 km/h) and the notificationsound prohibition is cancelled when this condition is satisfied.Consequently, when a driver turns the mute switch 16 ON while thevehicle speed V is below the D sound fade-out speed (30 km/h) (i.e.,while the vehicle speed is in a low vehicle speed region where theforward moving notification sound D is emitted), the prohibition of thenotification sounds is not cancelled when the driver's finger leaves themute switch 16. Instead, the prohibition continues and the problem of anotification sound being emitted while the vehicle is traveling in aplace where the notification sound can be a disturbance to a person(e.g., a pedestrian) in a surrounding area can be avoided.

When the vehicle is traveling at or in an area surrounding amanufacturing plant, a busy shopping area, or other noisy place (e.g., aplace where a noise level is high), it may be difficult for a person(e.g., a pedestrian) in a surrounding area to hear the starting forwardmovement notification sound S, the forward moving notification sound D,the reverse movement notification sound R or other notification soundemitted from the cabin exterior speaker 1 and difficult for the purposeof the notification to be accomplished if the notification sound isemitted at a standard sound pressure level. In such a situation, adriver can issue a notification sound volume increase command bypressing a sound volume increasing switch 17 shown in FIG. 1. The soundvolume increasing switch 17 is configured to issue a notification soundvolume increase command each time it is pressed such that it enters anON state. When it is not being pressed, it automatically resumes anormal position (OFF position).

When the controller 12 receives the notification sound volume increasecommand from the sound volume increasing switch 17, the notificationsound controller 12 shown in FIG. 1 executes a control program shown inFIG. 6 and increases the volume of the notification sounds as will nowbe explained. In step S61, the controller 12 checks if the sound volumeincreasing switch 17 has been turned ON, i.e., if the notification soundvolume increase command has been issued. If the sound volume increasingswitch 17 is not ON (if the notification sound volume increase commandhas not been issued), then the controller 12 ends the control loop anddoes not execute a volume increase of the notification sounds. As aresult, the notification sounds are emitted as explained previously withreference to FIGS. 2 to 4 and the sound pressure level of thenotification sounds remains at a standard value.

If the controller 12 determines in step S61 that the sound volumeincreasing switch 17 is ON (i.e., that the notification sound volumeincrease command has been issued), then the controller 12 proceeds tostep S62 and increases the volume of the notification sounds such that anotification sound (S sound, D sound, or R sound) emitted from the cabinexterior speaker 1 in accordance with the controls explained in FIGS. 2to 4 is emitted at a higher sound pressure level than the standardvalue.

In step S63, the controller 12 determines if a prescribed amount of time(e.g., one minute) has elapse since the sound volume increasing switch17 was turned ON (i.e., since the notification sound volume increasecommand was issued). If the determination result is No, i.e., if theprescribed amount of time still has not elapsed since the sound volumeincreasing switch 17 was turned ON (i.e., since the notification soundvolume increase command was issued), then the controller 12 ends thecontrol loop and continues executing the notification sound volumeincrease started in step S62. When the controller 12 determines in stepS63 that the prescribed amount of time has elapsed since the soundvolume increasing switch 17 was turned ON (i.e., since the notificationsound volume increase command was issued), the controller 12 proceeds tostep S64 and cancels the notification sound volume increase executed instep S62, thereby lowering the sound pressure level of the notificationsounds (the S sound, the D sound and the R sound) emitted from the cabinexterior speaker 1 in accordance with the controls shown in FIGS. 2 to 4back to the standard value.

With the notification sound volume increase control described above,when the vehicle is traveling at or in an area surrounding amanufacturing plant, a busy shopping area, or other noisy place where itmay be difficult for a person in a surrounding area to hear anotification sound emitted from the cabin exterior speaker 1, a drivercan increase a volume of the notification sounds by pressing the soundvolume increase switch 17 (step S61) such that the controller increasesa sound pressure level (step S62) of the notification sounds (the Ssound, the D sound and the R sound) emitted from the cabin exteriorspeaker 1 in accordance with the controls shown in FIGS. 2 to 4. In thisway, a person in a surrounding area is enabled to hear a notificationsound emitted from the cabin exterior speaker 1 even at or in an areasurrounding a manufacturing plant, a busy shopping area, or other noisyplace.

If the increased volume state of the notification sounds were tocontinue after the sound volume increasing switch 17 is pressed by adriver, then the notification sounds would be too loud when the vehicletraveled to a residential area or other less noisy place (i.e., a placewith a low noise level) and become a disturbance to people in asurrounding area. In particular, in this embodiment, the forward movingnotification sound D is a pseudo engine sound in a comparatively highfrequency range that does not readily enter the cabin interior fromoutside the cabin. Since the forward moving notification sound D isdifficult for a driver inside the cabin to hear, it is easy for thedriver to forget to return (lower) the volume level. Therefore, thisembodiment is configured to cancel the volume increase of thenotification sounds (step S64) when a prescribed amount of time haselapsed (step S63) since the sound volume increasing switch 17 wasturned on (i.e., since the notification sound volume increase commandwas issued), thereby lowering the sound pressure level of thenotification sounds (the S sound, the D sound and the R sound) emittedfrom the cabin exterior speaker 1 in accordance with the controls shownin FIGS. 2 to 4 back to a standard level.

Thus, it is assumed that by the time the prescribed amount of time haselapsed since the sound volume increasing switch 17 was turned ON, thevehicle will have traveled to a less busy suburban area, residentialarea, or other quieter place. By lowering the notification sounds (the Ssound, the D sound and the R sound) emitted from the cabin exteriorspeaker 1 back to the standard sound pressure level, the increasedvolume of the notification sounds resulting when the sound volumeincreasing switch 17 is turned ON can be prevented from disturbingpeople in a near the vehicle when the vehicle is in a quieter place.

The operational effects of a notification sound emitting apparatusaccording to this embodiment will now be explained.

With a conventional notification sound emitting apparatus, sinceemission of the forward moving notification sound is stopped when thevehicle stops, the notification sound turns on and off frequently whenthe vehicle is traveling on a congested road and starting and stoppingrepeatedly for short intervals. This turning on and off of thenotification sound can become an annoyance to a person outside thevehicle. Therefore, with the illustrated embodiment, when the vehicleenters a near stopped state (vehicle speed V≦Vs) including a stoppedstate (vehicle speed V=0 km/h) while the forward moving notificationsound (D sound) is being emitted, the forward moving notification soundis continued without fading out until a set amount of time (10 seconds)has elapsed since the vehicle stopped. As a result, when the vehicle istraveling on a congested road and starting and stopping repeatedly forshort intervals, the forward moving notification sound merely continuesto be emitted and avoids being turned on and off repeatedly. Since theset amount of time is shorter than an amount of time spent waiting at atraffic light, the forward movement notification sound will not continuewhen the vehicle is waiting at a traffic light.

Also in the illustrated embodiment, the notification sound controller 12is configured to emit a starting forward movement notification sound Simmediately before the vehicle starts moving forward in order to informa person outside the vehicle that the vehicle will start to move in aforward direction. As a result, a situation in which the startingforward movement notification sound and the forward movementnotification sound turn on and off in succession can be prevented whenthe vehicle is traveling on a congested road. In other words, if theembodiment were configured in the conventional fashion such that theforward moving notification sound is stopped any time the vehicle stops,then the starting forward movement notification sound and the forwardmoving notification sound would both repeatedly turn on and off insuccession and become even more of an annoyance.

Further in the illustrated embodiment, the notification sound controller12 is configured such that when a driving continuance intent determiningsection (step S35) determines that the driver does not intend tocontinue driving the vehicle, the controller 12 stops emission of theforward moving notification sound D even if the set amount of time hasnot elapsed since the vehicle assumed a stopped state. As a result, theforward moving notification sound D does not continue to be emitted in asituation where the vehicle will not start moving again such that apedestrian can be protected from being confused by a notification soundemitted in such a situation.

In addition, with this embodiment, the forward moving notification soundis faded out when the shift position is changed from the D range to anon-driving range, i.e., the P range or the N range, even if the setamount of time has not yet elapsed. A change of the shift position to anon-driving range indicates that the driver does not intend to continuedriving, i.e., that the driver does not intend to start the vehicle intomotion again. In such a case, it is preferable to stop the forwardmoving notification sound even though the set amount of time has notelapsed because the possibility that the forward moving notificationsound will be turned on and off repeatedly no longer exists and apedestrian might be confused by the forward movement notification soundif it continues while the vehicle is stopped.

Moreover, in the illustrated embodiment, the driving continuance intentdetermining section is configured to determine that a driver does notintend to continue driving when a shift position has been changed fromthe forward driving range (D range) to a non-driving range (N range or Prange). As a result, a driver's intent to continue driving can bedetermined accurately.

While only selected embodiments have been chosen to illustrate thepresent invention, it will be apparent to those skilled in the art fromthis disclosure that various changes and modifications can be madeherein without departing from the scope of the invention as defined inthe appended claims. Also it is not necessary for all advantages to bepresent in a particular embodiment at the same time. Every feature whichis unique from the prior art, alone or in combination with otherfeatures, also should be considered a separate description of furtherinventions by the applicant, including the structural and/or functionalconcepts embodied by such feature(s). Thus, the foregoing descriptionsof the vehicle notification sound emitting apparatus are provided forillustration only, and not for the purpose of limiting the invention asdefined by the appended claims and their equivalents.

1. A vehicle notification sound emitting apparatus comprising: a sound emitting device configured to emit a movement notification sound to outside of a vehicle to inform a person in an area surrounding the vehicle that the vehicle will move; and a notification sound control device configured to operate the sound emitting device to continue to emit a movement notification during a period from when a vehicle speed becomes equal to or smaller than a prescribed value until a prescribed amount of time has elapsed in a situation where the vehicle speed becomes equal to or smaller than the prescribed value while the movement notification sound is being emitted.
 2. The vehicle notification sound emitting apparatus as recited in claim 1, wherein the notification sound control device is configured to sets the prescribed value to a vehicle speed that is indicative of a stopped state.
 3. The vehicle notification sound emitting apparatus as recited in claim 1, wherein the notification sound control device is configured to emit the movement notification sound immediately before the vehicle starts moving to inform a person outside the vehicle that the vehicle will start to move.
 4. The vehicle notification sound emitting apparatus as recited in claim 1, wherein the notification sound control device includes a driving continuance intent determining section configured to determine a driving continuance intent of a driver, and the notification sound control device is further configured to stop emission of the movement notification sound when the vehicle stops while the movement notification sound is being emitted and the driving continuance intent determining section is determined that the driver does not intend to continue driving.
 5. The vehicle notification sound emitting apparatus as recited in claim 4, wherein the driving continuance intent determining section is further configured to determine that a driver does not intend to continue driving when a shift position has been changed to a non-driving position.
 6. The vehicle notification sound emitting apparatus as recited in claim 2, wherein the notification sound control device is configured to emit the movement notification sound immediately before the vehicle starts moving to inform a person outside the vehicle that the vehicle will start to move.
 7. The vehicle notification sound emitting apparatus as recited in claim 6, wherein the notification sound control device includes a driving continuance intent determining section configured to determine a driving continuance intent of a driver, and the notification sound control device is further configured to stop emission of the movement notification sound when the vehicle stops while the movement notification sound is being emitted and the driving continuance intent determining section is determined that the driver does not intend to continue driving.
 8. The vehicle notification sound emitting apparatus as recited in claim 7, wherein the driving continuance intent determining section is further configured to determine that a driver does not intend to continue driving when a shift position has been changed to a non-driving position.
 9. The vehicle notification sound emitting apparatus as recited in claim 2, wherein the notification sound control device includes a driving continuance intent determining section configured to determine a driving continuance intent of a driver, and the notification sound control device is further configured to stop emission of the movement notification sound when the vehicle stops while the movement notification sound is being emitted and the driving continuance intent determining section is determined that the driver does not intend to continue driving.
 10. The vehicle notification sound emitting apparatus as recited in claim 9, wherein the driving continuance intent determining section is further configured to determine that a driver does not intend to continue driving when a shift position has been changed to a non-driving position.
 11. The vehicle notification sound emitting apparatus as recited in claim 3, wherein the notification sound control device includes a driving continuance intent determining section configured to determine a driving continuance intent of a driver, and the notification sound control device is further configured to stop emission of the movement notification sound when the vehicle stops while the movement notification sound is being emitted and the driving continuance intent determining section is determined that the driver does not intend to continue driving.
 12. The vehicle notification sound emitting apparatus as recited in claim 11, wherein the driving continuance intent determining section is further configured to determine that a driver does not intend to continue driving when a shift position has been changed to a non-driving position. 